TORONTO -- It looked as though Mike Fiers was in control early in his outing against the Blue Jays on Sunday. But everything unraveled for the big right-hander in the fifth inning.

Fiers has surrendered his fair share of home runs, but he has been at his best when limiting the damage. On Sunday, he allowed a two-run home run to Troy Tulowitzki and a home run to Russell Martin on back-to-back pitches in the fifth inning, and found himself heading to the showers after that sequence in Toronto's eventual 9-2 win.

The inning saw a 2-1 Toronto lead expand to 5-1. While Houston still finished its road trip 4-3, Fiers admitted the feeling isn't the same after the loss on Sunday, and was quick to absorb the blame.

"I didn't want to give [Tulowitzki] anything too good," Fiers said. "I had a base open and I fell behind 3-0, tried to throw him a strike and he capitalized on 3-1. I tried to keep it down and away and it leaked over more than I wanted to, and he made me pay for it. That was a big moment in the game, and then obviously the home run afterward and I was out."

Fiers allowed multiple home runs for the sixth time this season -- and second straight outing. The 31-year-old sits 11th in the American League with 22 home runs allowed this season, just two off his total from last season.

"They never let up," Astros manager A.J. Hinch said. "Their offense is pretty potent when it gets going. When they get the lead as they did today, they can hunt some pitches to hit. They hit the ball out of the ballpark. We didn't really have an answer to stop them."

Fiers' 4 2/3 innings was the sixth time this season he's been unable to complete five innings, and it stands out in comparison to his last outing against the Blue Jays. On Aug. 4 at Minute Maid Park, Fiers allowed just two runs in six frames.

The outing caused a ripple effect on the Astros' bullpen. Already short Ken Giles -- who is on the paternity leave list for the weekend -- and Chris Devenski after the reliever started in Thursday's doubleheader against the Twins, Hinch was forced to burn through five relievers to close out the game, and used James Hoyt as well as Jandel Gustave for the second time in as many days.

"It's a team that's tough to match up against," Hinch said. "They handle a little bit of everything when they're going right. We're going through some growing pains a little bit with some of these young kids. They're learning that mistakes get hit up here. We'll continue to grind through it. We'll have our full bullpen back by Tuesday [against St. Louis]. That'll be a nice return."